U.S. patent number 4,147,464 [Application Number 05/887,139] was granted by the patent office on 1979-04-03 for hole cutter for hard materials such as ceramic tile.
This patent grant is currently assigned to American Olean Tile Company, Inc.. Invention is credited to Wayne C. Watson, Jonas W. Weisel.
United States Patent |
4,147,464 |
Watson , et al. |
April 3, 1979 |
Hole cutter for hard materials such as ceramic tile
Abstract
A hole cutter for hard material such as ceramic tile. The cutter
has a cylindrical body which has an axial opening and a pilot drill
is mounted therein. The drill and the opening are non-circular, for
example, hexagonal, in order to prevent relative rotation between
the drill and the body. The body has a plurality of axially
extending recesses in its periphery and an axially extending
cutting blade which has an arcuate cross-section is positioned in
each recess. The drill and the blades have carbide tips. The tips
on the blades have beveled outer corners which prevent them from
radially spreading when drilling and which minimize chipping the
tile or its glaze. Mounting holes through the blades and in the
recesses are spaced circumferentially away from their center lines
to prevent improper mounting.
Inventors: |
Watson; Wayne C. (Ambler,
PA), Weisel; Jonas W. (Line Lexington, PA) |
Assignee: |
American Olean Tile Company,
Inc. (Lansdale, PA)
|
Family
ID: |
25390516 |
Appl.
No.: |
05/887,139 |
Filed: |
March 16, 1978 |
Current U.S.
Class: |
408/206; 408/226;
408/231; 408/703 |
Current CPC
Class: |
B23B
51/05 (20130101); Y10T 408/9098 (20150115); Y10S
408/703 (20130101); Y10T 408/907 (20150115); Y10T
408/8957 (20150115) |
Current International
Class: |
B23B
51/05 (20060101); B23B 51/04 (20060101); B23B
041/02 (); B23B 051/00 () |
Field of
Search: |
;408/200,201,204,206,208,209,214,216,223,224,225,231,226,703
;407/42,116 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hinson; Harrison L.
Attorney, Agent or Firm: Leonard; Henry K.
Claims
Having described our invention, we claim:
1. A hole cutter for hard materials, such as ceramic tile, said
cutter comprising, in combination,
(a) a generally cylindrical body having an axial opening
therethrough and a plurality of axially extending recesses in its
periphery, each of such recesses having parallel axially extending
side walls,
(b) a pilot drill shaft mounted non-rotatably in and extending
axially through the axial opening in said body,
(c) a plurality of cutting blades, each of said blades having an
axially extending shank of arcuate cross-section that is adapted to
fit into one of the recesses in said body,
(d) a cutting tip on each of said shanks, said tip having a
rearwardly raked end and a beveled, radially outward side,
(e) means for releasably securing said body on said pilot drill
shaft, and
(f) means for removably securing said cutting blades in the
recesses in said body.
2. A hole cutter according to claim 1 in which all of the cutting
blades are identical and each of said blades has a mounting hole
through its shank which is circumferentially offset from the axial
center line of said shank and in which there is a radial hole in
the base of each recess that is aligned with the mounting hole in
said shank when said blade is in one of the recesses and the means
for securing each of said blades in one of the recesses extends
through the aligned holes, whereby improper mounting of a cutting
blade on the body is prevented.
3. A hole cutter according to claim 1 in which the depth of the
recesses in said body is at least equal to the radial thickness of
the cutting blade shanks.
4. A hole cutter according to claim 1 in which the axially
extending recesses in the periphery of the body have radially inner
sides that lie in planes that are normal to a radius of said
body.
5. A hole cutter for hard materials such as ceramic tile, said
cutter comprising, in combination,
(a) a generally cylindrical body having an axial opening
therethrough,
(b) a pilot drill shaft mounted non-rotatably in and extending
axially through the axial opening in said body,
(c) a plurality of cutting blades, each of said blades having an
axially extending shank of arcuate cross-section that is
approximately concentric with the periphery of said body,
(d) a cutting tip on each of said shanks, said tip having a
rearwardly raked end and a beveled radially outward side,
(e) means for releasably securing said body on said pilot drill
shaft, and
(f) means for removably securing said cutting blades in the
periphery of said body.
6. A hole cutter according to claim 5 in which the axial opening in
the body is polygonal in cross-section and the pilot drill shaft is
complementary thereto.
Description
BACKGROUND OF THE INVENTION
While many different types of rotary hole saws or hole cutters have
been suggested in the past, none of them has been entirely
satisfactory for cutting holes in ceramic tile, particularly in
ceramic tiles which have hard glazed surfaces, such as those used
for bath tub enclosures and the like. So-called diamond core drills
and carbide grit hole saws have been recommended for use on ceramic
tile.
While a diamond core drill will, of course, cut through a ceramic
tile, experience has shown that a water spray must be employed to
cool the drill while it is cutting or the diamonds will be lost.
Not only does this necessitate auxiliary equipment to supply the
cooling water, but the tiles become saturated with water which
tends to make them incompatible with adhesives used to hold the
tile in place.
Hole saws with carbide grit bonded to their teeth also will cut
through ceramic tile. However, actual tests have shown that such a
saw will only cut a few holes before much of the carbide grit is
lost and, of course, the grit cannot be replaced nor can the saw be
re-sharpened.
It is therefore the principal object of the instant invention to
provide a hole cutter for hard materials, such as ceramic tile,
which is so designed as to minimize the chipping of the hard
material and particularly the glazed surfaces of ceramic tile when
a hole is being cut.
A further object is to provide a hole cutter having cutting blades
which have carbide tips thereby providing a long life and which
readily can be removed and replaced when necessary.
Another object of the instant invention is to provide a rotary hole
cutter for ceramic tile which is so designed as to minimize
"chattering" and the resulting irregularities in the hole
edges.
It is yet another object of the instant invention to provide a hole
cutter for ceramic tile wherein relative rotation between the pivot
drill and the cutter body is eliminated and where the tendency of
the cutters mounted on the body to flare outwardly is
minimized.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in side elevation of a hole cutter embodying the
invention, the cutter being shown on a scale larger than that which
normally is utilized for the purpose intended;
FIG. 2 is a top plan view of the cutter shown in FIG. 1; and
FIG. 3 is a greatly enlarged view in perspective of one of the
cutter blades with which a hole cutter embodying the invention is
equipped.
DESCRIPTION OF PREFERRED EMBODIMENT
A hole cutter embodying the invention has a cylindrical body 10 in
which there is formed, preferably by broaching, an axial opening 11
of non-circular cross-section, in this case hexagonal, although, of
course, the hole may be of some cross-section other than hexagonal
so long as it is non-circular. A pilot drill 12 has a shaft 13 of
cross-section that is complementary to the hole 11, in this case,
also being of hexagonal cross-section. The pilot drill 12 has a
carbide tip 14 which, in usual fashion, is set into a transverse
slot and secured by appropriate silver soldering. The pilot drill
12 is held in place, i.e., protruding a desired distance beyond the
body 10, by a set screw 15 which is threaded into a radial tapped
hole 16 in the body 10.
A cutting blade 20 is positioned in each of the recesses 17. Each
of the cutting blades 20 has an elongated shank 21 which is arcuate
in cross-section as best can be seen in FIG. 2. The shank 21 is of
such circumferential width as to nest snugly in one of the recesses
17 and of such axial length as to protrude forwardly from the body
10 a distance greater than the thickness of the material through
which the hole is to be cut.
Each of the cutting blade shanks 21 has a hole 22 which is
circumferentially offset from the median line of the shank 21 as
best can be seen in FIG. 1. A tapped hole 23 in the body 10 opening
into the respective recess 17 similarly is offset circumferentially
from the medial line of the recess so as to align with the hole 22
in the cutting blade shank 21 when the cutting blade 20 is in
position in the respective recess. Each of the cutting blades 20 is
retained in one of the recesses 17 by a machine screw 21 and, when
the screw 21 is tightened in place, it slightly flexes the arcuate
shank 21 and the resiliency of the shank 21 thrusting outwardly
against the head of the screw 24 binds the screw 24 so that it is
less likely to become loosened. By thus circumferentially
offsetting the holes 22 and the tapped holes 23 from the median
lines of the cutting blade shanks 21 and the recesses 17, improper
or reverse mounting of the cutting blades 21 in the recesses 17 is
prevented.
Each of the cutting blades 20 has a carbide tip 25 which is
soldered in a recess (unnumbered) cut in the leading end of the
respective shank 21. As can best be seen in FIG. 1, both the end of
the cutting blade shank 21 and the tip 25 are cut backwardly and
downwardly relative to the direction of rotation to provide a raked
end on each of the cutting blades 20.
In addition, and importantly according to the invention, the
radially outward side of each of the tips 25 is beveled as
indicated by the reference number 26 so that as the cutting blades
move into the work piece, i.e., into the surface of the ceramic
tile in which the hole is being bored, radially outward flexing of
the cutting blades 20 is prevented. Because the shanks 21 are
arcuate and are under some compression by reason of the tightening
of the screws 24, the shape of the shanks 21 also works against
outward flexing of the cutting tips 25 as they progress into the
work. As the cutting edges of the tips 25 cut into the surface of
the work piece, the beveled shoulders 26 begin to bear against the
surface and gradually and progressively cut a beveled edge away
from the hole being bored progressively counter boring the tile
body with the outside diameter of the hole being bored
predetermined by the radially outward side of the leading edge of
the beveled shoulders 26.
Because most ceramic tile through which holes would be bored does
not have a thickness greater than 1/4 inch or, even in the case of
heavy floor tiles, of 3/4 inch, the pilot drill 12 protrudes
through the tile prior to the boring of the hole and the cutting
blade tips 25 protrude far enough forwardly of the body 10 so that
the hole is completely bored through the ceramic tile prior to the
time that the surface of the tile would be engaged by the machine
screws 24.
* * * * *